Copper coated paper and cigarette wrapper paper

Abstract

The application provides a copper plate paper and cigarette paper thereof, and the copper plate paper comprises a base paper, a first coating layer, a second coating layer and a third coating layer; the base paper comprises a front surface and a back surface arranged oppositely; the first coating layer is coated on the front surface of the base paper; the second coating layer is coated on the back surface of the base paper, wherein the material of the second coating layer is selected from at least two or more combinations of sodium carboxymethyl starch, carboxymethyl cellulose, polyvinyl alcohol, AZC type (zirconium ammonium carbonate) adhesive and multi-active functional group high cross-linking type water resistance agent; and the third coating layer is coated on the second coating layer. The copper plate paper provided by the embodiment of the application can maximally inhibit the problem of inaccurate printing or gold blocking caused by shape stability of non-fluorescent cigarette paper single copper during printing and post-processing. The non-fluorescent cigarette paper single copper can fully meet the requirements of the current cigarette packaging market, increasingly exquisite and complex printing and subsequent processing quality.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of papermaking, in particular to a copper plate paper and a cigarette wrapper. BACKGROUND

[0002] Non-fluorescent cigarette wrapper single copper is a single-sided copper plate paper used for cigarette packaging. It contains no or very low content of fluorescent whitening agent to meet environmental protection and food safety requirements. In addition, as a single copper for cigarette packaging, it also needs to meet the quality and post-processing requirements, including:

[0003] 1) Surface fineness, the surface should be fine to meet the requirements of aluminum plating, suitable for various printing and processing methods.

[0004] 2) Accurate overprint, high accuracy of overprint to ensure accurate alignment of patterns and text.

[0005] 3) Anti-curling performance, good anti-curling performance to adapt to subsequent processing and packaging processes.

[0006] 4) Water resistance, good water resistance to protect cigarettes from moisture.

[0007] 5) Gold stamping, to increase the beauty and anti-fake property of the package, which may be gold stamped after printing by hot pressing the metal foil onto the packaging paper.

[0008] 6) Die cutting, which is to cut the printed large sheet material into individual small packages according to the design requirements, which requires accurate size control to ensure the consistency of each package.

[0009] 7) Laminating, to improve the wear resistance and protection of the cigarette package, a layer of plastic film may be laminated on the surface of the package.

[0010] The above quality and post-processing technology of non-fluorescent cigarette wrapper single copper requires that the non-fluorescent cigarette wrapper single copper has stable moisture state to avoid changes in moisture during the post-processing process (gold stamping, die cutting, etc.), which may cause poor dimensional stability and inaccurate overprint. Therefore, how to control the moisture stability of the single copper itself is the key to ensure the running property and post-processing quality of the non-fluorescent cigarette wrapper single copper during printing and post-processing.

[0011] With the increasingly fierce market competition between copper paper production enterprises and cigarette packet printing enterprises; each factory is improving the efficiency of the paper machine, and the paper speed is getting faster and faster. The longitudinal and lateral differences of the paper brought by the high-speed paper machine are more and more obvious. The quality risk brought by this is that the moisture of the paper changes under the influence of environmental temperature and humidity. Non-fluorescent cigarette packets with single copper are more prone to dimensional stability problems due to fiber shrinkage and swelling. In addition, in order to pursue higher processing efficiency, the specifications of the printing reels of the cigarette packet printing enterprises are also increasing. Large-size reels are more prone to dimensional stability problems during printing, gilding and other processes.

[0012] Therefore, it is of great significance to find a process scheme suitable for the high-speed paper machine process and the large-width printing process, which can still maintain high moisture stability, control the warping and dimensional stability of non-fluorescent cigarette packets with single copper, and is the urgent demand of non-fluorescent cigarette packet production enterprises to solve quality complaints. SUMMARY

[0013] The first aspect of the embodiment of the present application provides a copper paper, which comprises:

[0014] a base paper comprising a front surface and a back surface arranged oppositely;

[0015] a first coating layer coated on the front surface of the base paper;

[0016] a second coating layer coated on the back surface of the base paper, wherein the material of the second coating layer is selected from at least two or more combinations of sodium carboxymethyl starch, carboxymethyl cellulose, polyvinyl alcohol, AZC type (zirconium ammonium carbonate) adhesive, and multi-active functional group high cross-linking type water resistance agent;

[0017] a third coating layer coated on the second coating layer.

[0018] In some embodiments, the material of the second coating layer is a combination of sodium carboxymethyl starch, polyvinyl alcohol, and high cross-linking type water resistance agent.

[0019] In some embodiments, the degree of substitution of the sodium carboxymethyl starch is 0.5 to 0.7.

[0020] In some embodiments, the alcoholysis degree of the polyvinyl alcohol is 85-99%.

[0021] In some embodiments, the ratio of the absolute dry weight of the sodium carboxymethyl starch, the polyvinyl alcohol, and the high cross-linking type water resistance agent is 5 / 4 / 1.

[0022] In some embodiments, the total adhesive usage of the coating on the front surface and the back surface of the base paper is the same.

[0023] In some embodiments, the first coating layer and the third coating layer are the same coating, both including inorganic pigments and organic adhesives.

[0024] In some embodiments, the first coating layer includes a base coating layer and a top coating layer.

[0025] In some embodiments, the base coating layer includes enzyme-cut starch and SB latex, and the ratio of the absolute dry weight of the enzyme-cut starch to the SB latex is 6 / 8; the top coating layer includes SB latex.

[0026] In a second aspect, the embodiments of the present application provide a cigarette wrapper, which is prepared by using the copper plate paper described in the above embodiments.

[0027] The copper plate paper provided by the embodiments of the present application, on the basis of the existing high-speed cultural paper machine coating process, realizes the moisture stability of the cigarette wrapper copper plate paper by adjusting the formula of the base coating and the back coating, so that the moisture change fluctuation of the cigarette wrapper copper plate paper is controlled within ±1.0% in different temperature and humidity environments, thereby the problem of inaccurate printing or gold blocking caused by shape stability in the printing and post-processing process of the non-fluorescent cigarette wrapper single copper is maximally inhibited. The non-fluorescent cigarette wrapper single copper can fully meet the increasingly exquisite and complex printing and post-processing quality requirements of the current cigarette packaging market. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0029] Figure 1 is a structural schematic diagram of a copper plate paper in a conventional technical solution;

[0030] Figure 2 is a schematic diagram of the layer structure of an embodiment of the copper plate paper of the present application;

[0031] Figure 3 is a schematic diagram of the layer structure of another embodiment of the copper plate paper of the present application. DETAILED DESCRIPTION

[0032] The present application will be further described in detail below in combination with the drawings and embodiments. It is particularly pointed out that the following embodiments are only used to illustrate the present application, but do not limit the scope of the present application. Similarly, the following embodiments are only some embodiments of the present application, not all embodiments, and all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0033] The terms "first", "second", "third" in the embodiments of the present application are only used for descriptive purpose and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second", "third" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise explicitly and specifically limited. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative position relationship, movement condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications also change accordingly. The terms "include" and "have" and any variations thereof in the embodiments of the present application are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units is not limited to the listed steps or units, but can optionally include steps or units not listed, or can optionally include other steps or components inherent to the process, method, product or device.

[0034] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase that the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. As will be apparent to those of ordinary skill in the art, embodiments described herein can be combined with other embodiments.

[0035] In the conventional technical solution, high-speed cultural paper machines produce single copper, which is usually produced in a workshop environment with a temperature of 23-30℃ and a humidity of about 40-60%. However, printing and post-processing enterprises of cigarette packets are distributed throughout the country, and the climate and environmental temperature and humidity vary greatly in different places. Therefore, during the moisture rebalancing process of non-fluorescent cigarette packet single copper paper in different environments, the moisture of the paper can change significantly, and the fibers can swell and shrink due to moisture absorption and moisture release; thereby causing significant changes in size, and greatly increasing the risk of misregistration and gilding.

[0036] Please refer to Figure 1 , Figure 1 is a structural schematic diagram of a copper plate paper in the conventional technical solution, wherein the single-sided copper plate paper includes a base paper 10a, and a front coating layer 10b and a back coating layer 10c arranged on one side surface of the base paper 10a. Due to the different coating amounts of the coating layers on both sides, this kind of copper plate paper is prone to warping due to the different water absorption amounts of the two sides in a humid environment.

[0037] In view of this, the embodiments of the present application provide a laminated structure of a copper plate paper, please refer to Figure 2 ,Figure 2 is a schematic diagram of a laminated structure of an embodiment of the copper coated paper of the present application. The single-side copper coated paper 100 in the embodiment includes a base paper 110, a first coating layer 120, a second coating layer 130, and a third coating layer 140.

[0038] Specifically, the base paper 110 includes a front side 111 and a back side 112 arranged oppositely; the first coating layer 120 is coated on the front side 111 of the base paper 110; the second coating layer 130 is coated on the back side 112 of the base paper 110, and the third coating layer 140 is coated on the second coating layer 130.

[0039] In the embodiment, the material of the second coating layer 130 is selected from at least two or more combinations of sodium carboxymethyl starch, carboxymethyl cellulose, polyvinyl alcohol, AZC type (zirconium ammonium carbonate) adhesive, and multi-active functional group high cross-linking type water resistance agent. Optionally, the degree of substitution of the sodium carboxymethyl starch in the second coating layer 130 is 0.5 to 0.7. A too low degree of substitution results in poor water retention performance, and a too high degree of substitution results in high viscosity affecting the coating operation. The second coating layer 130 can greatly reduce the sensitivity of the fibers on the back side of the base paper 110 to water, effectively reducing the speed of moisture absorption and moisture dispersion of the fibers on the back side in the environment, thereby improving the warping condition of the single copper.

[0040] Optionally, the coating materials of the first coating layer 120 and the third coating layer 140 can be the same and both include inorganic pigments and organic adhesives, wherein the inorganic pigments can include ground calcium carbonate, coating calcium carbonate, and porcelain clay. The organic adhesives include biological adhesive materials with starch or potato powder as the main material.

[0041] Optionally, referring to Figure 3 , Figure 3 is a schematic diagram of a laminated structure of another embodiment of the copper coated paper of the present application. The single-side copper coated paper 100 in the embodiment also includes a base paper 110, a first coating layer 120, a second coating layer 130, and a third coating layer 140.

[0042] The base paper 110 can also include a front side 111 and a back side 112 arranged oppositely; the first coating layer 120 is coated on the front side 111 of the base paper 110; the second coating layer 130 is coated on the back side 112 of the base paper 110, and the third coating layer 140 is coated on the second coating layer 130.

[0043] The material of the second coating layer 130 in the embodiment is selected from at least two or more combinations of sodium carboxymethyl starch, carboxymethyl cellulose, polyvinyl alcohol, AZC type (zirconium ammonium carbonate) adhesive, and multi-active functional group high cross-linking type water resistance agent. Optionally, the degree of substitution of the sodium carboxymethyl starch in the second coating layer 130 is 0.5 to 0.7, and the degree of substitution of the sodium carboxymethyl starch can be specifically 0.5, 0.51, 0.55, 0.60, 0.62, 0.68, and 0.7, etc. If the degree of substitution is too low, the water retention performance is poor, and if the degree of substitution is too high, the viscosity is high, which affects the coating operation. The second coating layer 130 can greatly reduce the sensitivity of the fibers on the back surface of the base paper 110 to water, effectively reducing the speed of moisture absorption and moisture dispersion of the back surface fibers in the environment, thereby improving the warping condition of the single copper.

[0044] Optionally, in an embodiment, the material of the second coating layer 130 can be a combination of sodium carboxymethyl starch, polyvinyl alcohol, and high cross-linking type water resistance agent, and the absolute dry weight ratio of the three is 5 / 4 / 1. The alcoholysis degree of the polyvinyl alcohol is 85-99%. In an embodiment, the absolute dry weight ratio of the sodium carboxymethyl starch (degree of substitution 0.7), polyvinyl alcohol (alcoholysis degree 99%), and high cross-linking type water resistance agent is 5 / 4 / 1.

[0045] Optionally, the coating of the first coating layer 120 and the third coating layer 140 can be the same and both include inorganic pigments and organic adhesives, wherein the inorganic pigments can include ground calcium carbonate, coating calcium carbonate, and porcelain clay, etc. The organic adhesives include biological adhesives with starch or potato powder as the main material.

[0046] Unlike the foregoing embodiments, the first coating layer 120 in the embodiment includes a base coating layer 121 and a top coating layer 122, wherein the base coating layer 121 includes enzyme-cut starch and SB latex (styrene-butadiene), and the absolute dry weight ratio of the enzyme-cut starch and the SB latex is 6 / 8; and the top coating layer includes SB latex.

[0047] In addition, by optimizing and balancing the total amount of the adhesives on the front and back surfaces of the non-fluorescent cigarette package single copper, especially the amount of the cross-linking type water resistance agent, the air permeability of the front and back coating layers can be effectively controlled and balanced, and the shape stability problem caused by the sharp change of the moisture on the single surface can be avoided.

[0048] Please refer to the following table, which is the coating amount of copper plate paper in a conventional technical solution.

[0049]

[0050] The front coating (Binder) material type is selected from common enzyme-digested starch (S in the table) and SB latex (L in the table), and the total application amount is 0.45+0.60+0.85=2.25g; and the back coating Binder is selected from SB latex, and the total application amount is only 0.45g, and the difference between the two sides is 1.80g; therefore, the back coating has open pores, and the back side is easily affected by the temperature and humidity environment and the drying process, resulting in a large fluctuation of the moisture content of the single copper, which is 3-5% higher in a high humidity environment than in a low humidity environment.

[0051] For comparison, please refer to the following table, which is the coating amount of the copper-coated paper according to an embodiment of the present application.

[0052]

[0053] The front Binder type and total amount are the same as those of the common cigarette package single copper scheme, i.e. 0.45+0.60+0.85=2.25g;

[0054] Back side: the back coating layer is selected from at least two or more combinations of carboxymethyl starch sodium CMS (degree of substitution range 0.5-0.7), carboxymethyl cellulose CMC, polyvinyl alcohol (alcoholysis degree 85-99mol%), AZC type water-resistant agent and multi-active functional group high-crosslinking type water-resistant agent. The scheme according to an embodiment of the present application is: CMS (optimal degree of substitution 0.7) / polyvinyl alcohol PVA (optimal alcoholysis degree 99%) / high-crosslinking type water-resistant agent=5 / 4 / 1 (absolute dry ratio), and the application amount is 1.8g; the back coating Binder is selected from SB latex, and the total application amount is 0.45g. Therefore, the total amount of the back Binder is 1.8g+0.45g=2.25g;

[0055] The high-moisture stability cigarette package copper-coated paper coating Binder scheme in the embodiment of the present application has a total amount of the front and back Binders, thereby maximizing the balance of the front and back Binders under the current coating amount process.

[0056] The following will list several specific embodiments for effect comparison and description.

[0057] Blank group: front CT1 standard primer Pigment--C65=100% (100par), S / L=6 / 8 (S=enzyme-digested starch, L=SB latex), CT3 standard topcoat Pigment--C95=100par, L=10.5 (L=SB latex); back side formula: CT4 standard back coating Pigment--C65=100par, L=9 (L=SB latex); the Cobb value of the single copper, the moisture content under different humidity environments and the maximum difference value data are shown in the attached table.

[0058] Example 1: The front CT1 / CT3, back CT4 formula and coating amount are the same as the blank group. The back CT2 surface sizing formula: CMS solution, absolute dry coating amount 1.5g; the Cobb value of single copper, moisture under different humidity environments, and maximum moisture difference data are shown in the table.

[0059] Example 2: The front CT1 / CT3, back CT4 formula and coating amount are the same as the blank group. The back CT2 surface sizing formula: CMC solution, absolute dry coating amount 1.5g; the Cobb value of single copper, moisture under different humidity environments, and maximum moisture difference data are shown in the table.

[0060] Example 3: The front CT1 / CT3, back CT4 formula and coating amount are the same as the blank group. The back CT2 surface sizing formula: CMS / PVA=5 / 5 absolute dry ratio, absolute dry coating amount 1.5g; the Cobb value of single copper, moisture under different humidity environments, and maximum moisture difference data are shown in the table.

[0061] Example 4: The front CT1 / CT3, back CT4 formula and coating amount are the same as the blank group. The back CT2 surface sizing formula: CMS / PVA / AZC water-resistant agent=4 / 3 / 3 absolute dry ratio, absolute dry coating amount 1.5g; the Cobb value of single copper, moisture under different humidity environments, and maximum moisture difference data are shown in the table.

[0062] Example 5: The front CT1 / CT3, back CT4 formula and coating amount are the same as the blank group. The back CT2 surface sizing formula: CMS / PVA / high cross-linking type water-resistant agent=5 / 3 / 3 absolute dry ratio, absolute dry coating amount 1.5g; the Cobb value of single copper, moisture under different humidity environments, and maximum moisture difference data are shown in the table.

[0063] Example 6: The front CT1 / CT3, back CT4 formula and coating amount are the same as the blank group. The back CT2 surface sizing formula: CMS / PVA / high cross-linking type water-resistant agent=5 / 4 / 1 absolute dry ratio, absolute dry coating amount 1.5g; the Cobb value of single copper, moisture under different humidity environments, and maximum moisture difference data are shown in the table.

[0064] Example 7: The front CT1 / CT3, back CT4 formula and coating amount are the same as the blank group. The back CT2 surface sizing formula: CMS / PVA / high cross-linking type water-resistant agent=5 / 4 / 1 absolute dry ratio, absolute dry coating amount 1.8g; the Cobb value of single copper, moisture under different humidity environments, and maximum moisture difference data are shown in the table.

[0065] Example 8: The front CT1 / CT3, back CT4 formula and coating amount are the same as the blank group. The back CT2 surface sizing formula: CMS / PVA / high cross-linking water-resistant agent = 5 / 4 / 1 dry weight ratio, dry coating amount 2.2g; the Cobb value of single copper, moisture under different humidity environments, and maximum moisture difference data are shown in the table.

[0066]

[0067]

[0068] The above test data shows that:

[0069] 1. Adding a surface sizing on the back CT2 can improve moisture stability;

[0070] 2. Among CMS, CMC, PVA, ACZ water-resistant agent and high cross-linking water-resistant agent, CMS / PVA / high cross-linking water-resistant agent has better effect on improving moisture stability;

[0071] 3. The best ratio of CMS / PVA / high cross-linking water-resistant agent is 5 / 4 / 1, and too much high cross-linking water-resistant agent will result in too low back Cobb value, thereby affecting the balance of the two sides' moisture absorption rate, and easy to cause warping.

[0072] 4. When the dry coating amount of surface sizing is about 1.8g, it can ensure that the total Binder dry amount of the front and back is equivalent under the existing coating amount conditions, thereby controlling the relatively balanced moisture absorption rate of the two sides' coating, and the paper is least affected by environmental changes, and the moisture stability of the paper is best.

[0073] The copper coated paper in the embodiments of the present application can be used on the base paper with large differences in length and width produced by the current high-speed cultural paper machine, and through the adjustment of the back coating formula outside the machine, it can realize high stability of the moisture of non-fluorescent cigarette package single copper, so that the non-fluorescent cigarette package single copper can maintain a relatively stable moisture state in different temperature and humidity environments in the country, thereby avoiding the problems that the size of the single copper cigarette package changes dramatically due to moisture fluctuation in printing and complex post-processing, and further affecting the customer's printing overprint, gold blocking text accuracy and other problems. In different humidity environments, the maximum moisture change is ≤1.5% (the maximum moisture change of ordinary cigarette package single copper is about 4.0%), thereby ensuring that the maximum shrinkage and swelling of the large width web (width more than 650mm) is controlled within 1.5mm.

[0074] Among them, the non-fluorescent cigarette package paper produced by using the copper coated paper in the embodiments of the present application can maximize the balance of the moisture absorption rate of the front and back coating, thereby ensuring that the small label does not warp and has better integrity in the cutting process after single copper printing and post-processing.

[0075] The above merely describes some embodiments of the present application, and does not limit the protection scope of the present application, and any equivalent device or equivalent process transformation using the content of the present application specification and drawings, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A copper plate paper, characterized by, The copperplate paper comprises: a base paper comprising a front side and a back side arranged oppositely; a first coating layer coated on the front side of the base paper; a second coating layer coated on the back side of the base paper, wherein the second coating layer has an absolute dry application amount of 1.8 g / m2, so that the total adhesive amount of the coatings on the front side and the back side of the base paper is the same; the material of the second coating layer is a combination of sodium carboxymethyl starch, polyvinyl alcohol and high cross-linking water-resistant agent, and the absolute dry amount ratio of the sodium carboxymethyl starch, the polyvinyl alcohol and the high cross-linking water-resistant agent is 5 / 4 / 1; a third coating layer coated on the second coating layer.

2. The art paper according to claim 1, characterized in that, The degree of substitution of the sodium carboxymethyl starch is 0.5 to 0.

7.

3. The art paper according to claim 2, characterized in that, The alcoholysis degree of the polyvinyl alcohol is 85-99%.

4. The art paper according to claim 1, wherein The coatings of the first coating layer and the third coating layer are the same, and both comprise inorganic pigments and organic adhesives.

5. The art paper according to claim 4, characterized in that, The first coating layer comprises a base coating layer and a surface coating layer.

6. The art paper according to claim 5, characterized in that, The base coating layer comprises enzyme-cut starch and SB latex, and the absolute dry amount ratio of the enzyme-cut starch and the SB latex is 6 / 8; the surface coating layer comprises SB latex.

7. A cigarette paper, characterized in that, The cigarette paper is prepared by using the copperplate paper according to any one of claims 1-6.

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